Tightening system



FIG. 1 is a top, front, right side perspective view of a tightening system showing my new design;

FIG. 2 is a top plan view thereof, shown at an enlarged scale;

FIG. 3 is a bottom plan view thereof, shown at an enlarged scale;

FIG. 4 is a front elevation view thereof;

FIG. 5 is a right side elevation view thereof;

FIG. 6 is a left side elevation view thereof;

FIG. 7 is a rear elevation view thereof;

FIG. 8 is a top, front, right side perspective view of a second embodiment of FIG. 1, the only difference being the sheaves being shown in dotted lines and form no part of the second embodiment, it being understood that all other surfaces are the same as those of the first embodiment; and,

FIG. 9 is a top, front, right side exploded perspective view of the tightening system of FIG. 1.

The broken line showing in the drawings is for the purpose of illustrating portions of the tightening system and forms no part of the claim. 

CLAIM We claim the ornamental design for a tightening system, as shown and described. 